1. Field of the Invention
This invention relates to an apparatus for sharpening saw blades. More particularly, this invention relates to an apparatus which uses a grinder wheel to sharpen the tips or teeth of circular saw blades.
2. Description of the Prior Art
Effective sharpening of circular saw blades, particularly carbide-tipped saw blades, requires that careful attention be paid to the geometry of the saw blade tips or teeth. Depending on the type of blade being sharpened, a variety of different grinding operations are required to restore sharpness. Almost all saw sharpening involves face grinding, which must be done in accordance with the saw's specified hook angle. A bevel angle may be used in face grinding. Sharpening also frequently involves top grinding, which must be done in accordance with the saw's specified top clearance angle. Grinding the top clearance angle may involve bevel angles and champfer or chip angles as well. For certain types of saws, side grinding is also done, in accordance with specified side clearance angles, which may be radial side clearance angles or tangential side clearance angles.
Several circular saw sharpening devices using grinding wheels are known in the prior art, including those shown in U.S. Pat. Nos. 1,768,996; 2,570,118; 2,808,743; 2,977,822; 3,313,185; 3,766,806; 3,815,446 and 3,960,037. A frequent disadvantage of prior art saw sharpening devices is that they are not versatile enough to permit all the different variations of face, top and side grinding which may be encountered. A further common disadvantage is that they are difficult to set up for the various types of grinding required. This is a matter both of ease and efficiency for the operator and a matter of accuracy. If an operator has difficulty seeing or setting up the angle relationships between the grinding wheel and the various surfaces of the saw tooth, grinds which accurately restore the desired angles will be difficult to achieve.